Effect of P1k3 on the transcriptional activity of p73 in H1299 cells / 中国癌症杂志

ABSTRACT

Background and purpose: Protein kinase P1k3 could increase the transcriptional activity of p53. However, the effect of P1k3 on the transcriptional activity of p73 is still unknown. Our study was to investigate the effect of P1k3 on the transcriptional activity of p73. Methods: Luciferase reporter assay, RT-PCR and colony formation assay were adopted to study the effect of P1k3 and kinase-deficient P1k3 (K52R) on the transcriptional activity of p73 in p53-deficient human lung carcinoma H1299 cells. Results: Luciferase reporter assay showed that p73 increased the luciferase activities induced by p21~(WAF1) and Bax promoters (P<0.05). After co-transfection with p73 and P1k3, the luciferase activities induced by p21~(WAF1) and Bax promotors were significantly decreased in a dose-dependent manner as compared with the group that transfected p73 only (P<0.05). However, kinase-deficient Plk3 (K52R) had no significant effect on the luciferase activities induced by p21~(WAF1) and Bax promoters (P>0.05). RT-PCR showed that p73 increased the mRNA expressions of p21~(WAF1) and BAX (P<0.05). P1k3 decreased the expressions of p21~(WAF1) and Bax induced by p73 (P<0.05). Kinase-deficient P1k3 (K52R) had no significant effect on the expressions of p21~(WAF1) and Bax induced by p73 (P>0.05). Colony formation assay revealed that p73 decreased the colony formation of H1299 cells (P<0.05). P1k3 decreased the inhibitory effect of p73 on the colony formation of H1299 cells (P<0.05). Kinase-deficient P1k3 (K52R) had no significant effect on the inhibitory effect of p73 on the colony formation of H1299 cells (P>0.05).Conclusion: P1k3 can inhibit the transcriptional activity of p73, where as kinase-deficient P1k3 has no effect on the transcriptional activity of p73.